| 草酸改性零价铁活化过硫酸盐降解地下水中2,4-DNT的研究 |
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| 引用本文： | 吴叔璇,韩旭,夏甫,杨昱,徐祥健,邓圣,姜永海.草酸改性零价铁活化过硫酸盐降解地下水中2,4-DNT的研究[J].环境科学研究,2022,35(1):108-118. |
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| 作者姓名： | 吴叔璇 韩旭 夏甫 杨昱 徐祥健 邓圣 姜永海 |
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| 作者单位： | 1.北京建工环境修复股份有限公司，污染场地安全修复技术国家工程实验室，北京 100015 |
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| 基金项目： | 国家自然科学基金项目(No.42007164)；;国家重点研发计划项目(No.2019YFC1806200)~~； |
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| 摘 要： | 2,4-二硝基甲苯(2,4-DNT)作为重要的化工原料，由于储存和生产过程中的“跑冒滴漏”，已然成为地下水中常见有毒有害污染物之一，对人体健康和生态环境安全造成极大威胁. 以草酸与商品零价铁为原料，通过球磨法制备草酸化零价铁(OA-ZVIbm)，并研究其活化过硫酸盐(PS)降解2,4-DNT的性能. 采用扫描电子显微镜(SEM)、X射线衍射(XRD)和傅里叶变换红外光谱(FT-IR)对活化剂进行表征，并考察活化剂和PS投加量、溶液初始pH及无机阴离子对2,4-DNT降解效果的影响. 结果表明:①通过球磨改性，零价铁表面氧化层被草酸亚铁壳层代替，加速铁核腐蚀生成Fe2+催化PS. ②在pH=7、0.2 g/L OA-ZVIbm和5 mmol/L PS的条件下，4.0 h内对50 mg/L 2,4-DNT降解率达到87.6%，降解过程符合准一级动力学方程. ③2,4-DNT降解率随OA-ZVIbm和PS投加量增加以及溶液初始pH的降低增加，但高浓度PS会抑制2,4-DNT的降解；NO3?、CO32?、Cl?和SO42?通过淬灭自由基或者与亚铁离子发生共沉淀，对降解产生不同程度的抑制效果. ④自由基淬灭试验表明，体系中同时产生SO4? ?、·OH和1O2，但SO4? ?在降解过程中起主导作用. ⑤降解中间产物鉴定表明，通过脱硝和氧化反应，2,4-DNT被降解成包括间苯二酚、丙二酸在内的毒性较小分子，可生化性显著提高. 研究显示，OA-ZVIbm能够高效活化PS，实现对地下水2,4-DNT的显著降解，具有一定的应用前景.
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| 关 键 词： | 零价铁 草酸 过硫酸盐(PS) 2 4-二硝基甲苯(2 4-DNT) 硫酸根自由基(SO4·?) |
| 收稿时间： | 2021-04-28 |
Enhanced Degradation of 2,4-DNT in Groundwater by Oxalic Acid-Modified Zero-Valent Iron as Persulfate Activator |
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| WU Shuxuan,HAN Xu,XIA Fu,YANG Yu,XU Xiangjian,DENG Sheng,JIANG Yonghai.Enhanced Degradation of 2,4-DNT in Groundwater by Oxalic Acid-Modified Zero-Valent Iron as Persulfate Activator[J].Research of Environmental Sciences,2022,35(1):108-118. |
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| Authors: | WU Shuxuan HAN Xu XIA Fu YANG Yu XU Xiangjian DENG Sheng JIANG Yonghai |
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| Affiliation: | 1.National Engineering Laboratory for Site Remediation Technologies, Beijing Construction Engineering Group Environmental Remediation Co., Ltd., Beijing 100015, China2.State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, China |
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| Abstract: | 2,4-dinitrotoluene (2,4-DNT), as an essential chemical raw material, has become one of common toxic and hazardous pollutants in groundwater due to runoff and leakage during storage and production, which poses a great threat to human health and ecological safety. To achieve efficient degradation of 2,4-DNT in groundwater, oxalated zero-valent iron (OA-ZVIbm) was prepared by ball milling of oxalic acid with commercial ZVI and further used as persulfate (PS) activator. The activator was characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The effects of activator and PS dosage, initial pH of the solution and inorganic anions on the degradation effect of 2,4-DNT were investigated. The results showed that: (1) The oxidized layer on the ZVI surface was replaced by a ferrous oxalate shell layer through the balling milling process, which accelerated the dissolution of ZVI to generate Fe2+ for PS activation. (2) Under the conditions of 0.2 g/L OA-ZVIbm, 5 mmol/L PS and 50 mg/L 2,4-DNT, the degradation of 2,4-DNT reached 87.6% within 4.0 h which consistent with pseudo primary kinetics. (3) With the increase of the dosage of OA-ZVIbm and PS and the decrease of the initial pH, the degradation rate of 2,4-DNT increased accordingly. The existence of NO3?, CO32?, Cl? and SO42? in the water exhibited different degrees of inhibition by quenching the free radicals and precipitating ferrous ions. (4) Quenching experiments verified that SO4? ?, 1O2 and ·OH were produced in the system, and SO4? ? played a dominant role in the degradation process. (5) The identification of degradation intermediates indicated that 2,4-DNT was degraded into less toxic molecules through oxidative denitrification, including resorcinol and malonic acid, and the biochemical properties were significantly improved. Overall, OA-ZVIbm has a promising application as a PS activator for organic pollutants degradation in the process of wastewater treatment. |
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